Conventionally, it has been known that an acoustic generator, a typical of which is a piezoelectric speaker, can be used as a small-sized and thin speaker. This acoustic generator can be used as a speaker to be incorporated into an electronic device such as a mobile phone and a flat panel television.
For example, the acoustic generator is provided with a vibration body and an exciter (piezoelectric vibration element) provided to the vibration body (see, for example, Patent Literature 1). It is configured to vibrate the vibration body by the piezoelectric vibration element and to generate a sound by using a resonance phenomenon of the vibration body.